Free printableMeasure partsTSP-ME-16
How to measure a scooter or ATV air filter
Filters are sold by shape and dimension, never by model. Four measurements and a fitting type settle it.
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TSP-ME-16 · version v1.0 · September 2026. Opens in your browser's PDF viewer, where you can print directly.
The problem it solves
Air filters are among the cheapest and most neglected parts on these machines, and they are almost never listed by model. They are listed by shape and size — and a filter that is close but wrong either will not seal or will not fit the housing, both of which let unfiltered air into the engine.
A restricted air filter chokes the engine and richens the mixture at the same time, which makes it a cause of two of the most commonly reported faults on these machines. It is also the cheapest thing to rule out. So it gets recommended constantly — and then the owner cannot find one that fits.
The reason is that filters are sold by physical description rather than by application. Once you have the element's dimensions and how it seals, any supplier can match it, and you are no longer restricted to sellers who happen to list your badge.
The measurement that catches people out is the sealing face. Two filters of identical outer dimensions can seal on a rubber flange, on a flat face, or by clamping over a spigot — and those are not interchangeable however well the outside matches.
The mistakes this sheet exists to prevent
- Measuring the filter housing instead of the element that sits in it.
- Ignoring how the element seals, so a correctly sized filter fits and lets unfiltered air past.
- Measuring a foam element while it is compressed or distorted.
- Fitting a bare foam filter with no oil on it when the original was oiled, which lets dust straight through.
- Reusing a paper element by blowing it out, which tears the paper from the wrong side.
Who it is for
- Anyone whose filter is missing, oil-soaked or disintegrating
- Owners diagnosing a rich mixture or poor top-end power
- Anyone who cannot find a filter listed for their machine
What is on it
- The four dimensions plus the sealing arrangement
- Element types and how each one seals
- A tracing area for irregular shapes
- An inspection list for the housing and ducting, which matter as much as the element
How to use it
- 01Take the element out and measure it, not the housing it came from.
- 02Let a foam element relax to its natural shape before measuring.
- 03Record how it seals — that is the dimension nobody quotes and everybody needs.
- 04Check the housing and intake ducting while it is apart.
Use it with the registry
Other sheets you may want
- How to measure and identify a Chinese scooter carburettorCarburettors are sold by a bore size and a family name that nobody explains. Measure yours and record the fittings before you order one.
- GY6 poor acceleration and no top speedIt runs, but it will not pull. The first question separates a transmission fault from an engine fault, and almost nobody asks it.
- GY6 maintenance schedule and service logA service record you build yourself from what your machine actually needs, rather than from a schedule invented for a machine nobody can identify.
Free to print, copy, and share — including in forums, clubs and workshops. If you find a mistake on this sheet, tell us and it gets corrected. Quote TSP-ME-16 and the version so we know exactly which sheet you mean. All printables.